BACKCOUNTRY ADVISORY 

As of Wednesday, March 10, 2004

A widespread avalanche cycle occurred on Sunday and Monday with the arrival and passage of a storm cycle in our region that deposited approximately 35 cm of new snow. The storm was accompanied by strong winds from the SE and SW at the mountaintops, and rising freezing levels.

Numerous natural and human-triggered avalanches were running during and after the storm cycle. While most of these were in the size 1.0-2.0 range involving storm snow layers from 20-40 cm in depth, a few of them were from size 2.5 to 3.0 with crown lines of up to 110 cm in depth. The initial failure plane of the larger releases is suspected to have been a buried layer of surface hoar that formed the first few day’s of March, stepping down to a temperature crust that formed on Valentine’s Day. Some large cornice failures also occurred throughout this period, some of them falling with little or no loading.

11 mm of rain fell on Monday night up to the 2,100 metre elevation. Temperatures began to plummet with the arrival of a cold front yesterday morning, resulting in a rapid stabilization of the surface layers of the snowpack. A melt-freeze crust can now be found on the surface on all aspects below 2,100 metres.

In many areas the warm temperatures and rainfall have likely negated many of the buried weaknesses within the upper levels of our snowpack.

Bear in mind that the stability of snow hinges on the integrity of the crust. As it begins to break down on solar aspects throughout the day, natural avalanche activity can be expected to begin to occur.

The avalanche danger is currently rated as LOW, however it will increase throughout the day with exposure to the sun.

Conditions may vary and can change rapidly. Check for the most current conditions before heading out into the backcountry. Daily updates for the areas adjacent to Whistler/Blackcomb are available at 604-938-7676, or at www.whistler-blackcomb.com/weather where there is also a link to the CAA public avalanche bulletin, or call 1-800-667-1105.

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